package com.zxf.field_method04;

public class Circle {
    double r;
    public void aera(){
        double pai =3.14;
        double s=pai * r*r;
        System.out.println("面积为" +s);
    }
     public double area2(double pai){
       double s= pai*r*r;
        return s;

     }


}
